Despite improvement of the vascular prostheses, the long term patency rate remains unfulfilled after small caliver graft implantation. Anastomotic neointimal hyperplasia (ANH) is known as a contributing factor of graft occlusion after implantation and the difference of mechanical properties between a vascular prosthesis and its host arteries, abnormal graft flow, intimal trauma due to surgical procedure, platelet aggregation in a surface of anastomotic site, suture material and method are suggested the factors of ANH.In this study, we investigated (1) the difference of mechanical properties between vascular grafts and host arteries. (2) small caliber(3mm in diameter) graft implantation in dogs and long term observation of the anastomotic site after implantation. (3) comparison of thrombogenecity of grafts and ANH. The results are as follows ;(1) A new type ultrasonic displacement meter was developed and compliance of arterial grafts ware measured. In comparison of compliance of human a
… Morerteries to that of grafts, a mismatch in compliance between grafts and arteries was obviously demonstrated.(2) In dogs, carotid artery was replaced with different compliance of graft (ePTFE, segmented polyurethane graft) 3mm in diameter and long term observation was performed. The rate of patency was good in high compliance graft (50%/1 year) but ANH was occurred both in low compliance graft and high compliant graft. Compliance mismatch between vascular prosthesis and host arteries is suggested to be one of the factor contributing ANH, but it seems to be not a main factor.(3) To evaluate relationship between platelet aggregation in a surface of graft and ANH. In^<111> platelet scintigraphy was performed in the early and late stage of graft implantation. There was significant difference of the patency rate between high platelet aggregation group and low plate let aggregation group in the early stage after implantation but there was no difference of occurrence of ANH between the two groups. Less